Communication protocol overlay

ABSTRACT

A communication protocol overlay that governs wireless data communications between an access point and subscribers. The communication protocol overlay includes a repeating pattern of superframes, each superframe including frames. Each frame includes a beacon emitted by an access point in a downlink communication to the subscribers at a beginning of the frame. Each frame further includes communication slots following the beacon. Each of the communication slots is uniquely assigned to one of the subscribers, permitting the subscriber to perform an uplink communication to the access point, within the communication slot. The beacon is precisely timed, and each of the communication slots follows the beacon with a specified temporal offset. A single superframe of the repeating pattern of superframes serves all subscribers by providing at least one communication slot to each of the subscribers.

BACKGROUND

Internet of Things (IoT) devices, such as locally placed sensors, may be used to gather data in various environments in a cost-effective manner. Wireless uplinks may be used to upload the gathered data. These wireless links may be operated using a communication protocol that establishes rules for communications between devices, for example between an IoT device and an access point. The communication protocol may be layered. The bottommost layer typically is the physical layer that describes the transmission and reception of raw bit streams over a physical medium. Additional abstraction layers may be placed on top of the physical layer to obtain additional functionalities. For example, a link layer may be established on top of the physical layer, enabling the transmission of data frames between two nodes that are connected by the physical layer. Additional layers may be placed on top of the link layer to obtain a higher level of abstraction, thus resulting in a protocol stack. If the protocol stack does not provide a desired functionality, an additional communication protocol overlay may be installed on top of the existing protocol stack.

SUMMARY

In general, in one aspect, the invention relates to a communication protocol overlay governing wireless data communications between an access point and a plurality of subscribers, the communication protocol overlay comprising: a repeating pattern of superframes, each superframe comprising a plurality of frames, wherein each frame of the plurality of frames comprises: a beacon emitted by an access point in a downlink communication to the plurality of subscribers at a beginning of the frame; a plurality of communication slots following the beacon, wherein each of the communication slots is uniquely assigned to one of the plurality of subscribers, permitting the subscriber to perform an uplink communication to the access point, within the communication slot, wherein the beacon is precisely timed, wherein each of the plurality of communication slots follows the beacon with a specified temporal offset, and wherein, a single superframe of the repeating pattern of superframes serves all subscribers of the plurality of subscribers by providing at least one communication slot to each of the subscribers.

In general, in one aspect, the invention relates to a method for synchronized transmission of data using an Internet of Things (IoT) protocol augmented with a communication protocol overlay, the method comprising: receiving, by a monitoring device and from an access point, a beacon, wherein the beacon establishes a time base; receiving from the access point, a network management message, wherein the network management message specifies time relative to the time base and frequency band for transmission of a data value by the monitoring device to the access point; collecting the data value by a sensing device of the monitoring device; making a determination that the time specified in the network management message is reached, and based on the determination: transmitting the data value using the frequency band specified in the network management message.

In general, in one aspect, the invention relates to a method for synchronized transmission of data using an Internet of Things (IoT) protocol augmented with a communication protocol overlay, the method comprising: obtaining, by an access point, from a network management, instructions to collect a data value by a sensing device of a monitoring device; transmitting, by the access point, a beacon; transmitting, by the access point, a network management message, comprising instructions to provide the data value, at a specified time and using a specified frequency band; receiving the data value from the monitoring device at the specified time and in the specified frequency band; forwarding the data value using a broadband uplink of the access point.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A-1H show systems for monitoring assets, in accordance with one or more embodiments of the invention.

FIGS. 2A and 2B show a hub-cloud configuration of a system for monitoring assets, in accordance with one or more embodiments of the invention.

FIGS. 3A-3G show access points of a system for monitoring assets, in accordance with one or more embodiments of the invention.

FIG. 4 shows a monitoring device of a system for monitoring assets, in accordance with one or more embodiments of the invention.

FIG. 5 shows a peripheral sensor of a system for monitoring assets, in accordance with one or more embodiments of the invention.

FIG. 6 shows the use of an IoT communication protocol overlay for communications between an access point and monitoring devices, in accordance with one or more embodiments of the invention.

FIG. 7 shows an exemplary IoT communication protocol overlay, in accordance with one or more embodiments of the invention.

FIG. 8 shows an exemplary frame of the IoT communication protocol overlay, in accordance with one or more embodiments of the invention.

FIG. 9 shows a communication slot reassignment in the IoT communication protocol overlay, in accordance with one or more embodiments of the invention.

FIG. 10 shows a first power saving scheme implemented using the IoT communication protocol overlay, in accordance with one or more embodiments of the invention.

FIG. 11 shows a second power saving scheme implemented using the IoT communication protocol overlay, in accordance with one or more embodiments of the invention.

FIG. 12 shows the use of the IoT communication protocol overlay for time difference of arrival (TDOA) positioning, in accordance with one or more embodiments of the invention.

FIG. 13 shows a computing system in accordance with one or more embodiments of the invention.

FIG. 14 shows a flowchart describing methods for monitoring assets, in accordance with one or more embodiments of the invention.

FIG. 15 shows a flowchart describing methods for transmitting, by a monitoring device, a data value.

FIG. 16 shows a flowchart describing methods for receiving, by an access point, a data value.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. Like elements may not be labeled in all figures for the sake of simplicity.

In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers does not imply or create a particular ordering of the elements or limit any element to being only a single element unless expressly disclosed, such as by the use of the terms “before,” “after,” “single,” and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In the following description of FIGS. 1A-16, any component described with regard to a figure, in various embodiments of the invention, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components will not be repeated with regard to each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments of the invention, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a horizontal beam” includes reference to one or more of such beams.

Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

It is to be understood that, one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope of the invention should not be considered limited to the specific arrangement of steps shown in the flowcharts.

Although multiple dependent claims are not introduced, it would be apparent to one of ordinary skill that the subject matter of the dependent claims of one or more embodiments may be combined with other dependent claims.

In general, embodiments of the invention are directed to methods and systems for monitoring assets. An asset may be anything of interest and/or value for which it is valuable to gather information about the status of the asset. Consider, the following examples:

-   -   A hospital that is specialized in the treatment of patients with         dementia. If these patients are allowed to move freely within         the hospital environment, it may be important to be able to         determine their location at any time. Further these patients may         suffer from additional conditions that may require continuous         monitoring of other variables such as heart rate, blood         pressure, etc.     -   In a luggage transportation system of a major airport, the         ability to locate any luggage item at any time, while being         processed by the luggage transportation system, would be highly         beneficial.     -   In the oil and gas industry, it may be beneficial to monitor         pipelines or other equipment to ensure safety and productivity.     -   In a warehouse, it may be useful to track employees, goods         and/or equipment to optimize operations.

Those skilled in the art will appreciate that the invention is not limited to the above examples. Embodiments of the invention may be used in any environment, including commercial, industrial, residential and natural environments of any size to monitor moving or stationary assets including, but not limited to, humans, animals, devices, products, or any other type of item. Further, the monitoring includes obtaining any type of information such as a location or a measurement of any variable.

FIGS. 1A-1H show systems for monitoring assets, in accordance with one or more embodiments of the invention. Turning to FIG. 1A, a monitored environment (100), in accordance with one or more embodiments of the invention, is shown. The monitored environment (100) may be any type of environment that is monitored using the monitoring system (110). A monitored environment may be, for example, an outdoor environment, e.g., in the oil and gas industry, or an area where environmental monitoring is performed, e.g., in a national park. A monitored environment may also be an indoor environment, for example, a warehouse, a school, a hospital, a prison, etc. A monitored environment may also include a combination of indoor and outdoor environments, e.g., when a campus of a public or private institution is monitored. Any environment that is equipped with a monitoring system (110) may be considered a monitored environment (100).

Within the monitored environment (100), monitored assets (102), may be tracked or monitored by the monitoring system (110). Monitored assets (102) may include stationary and/or moving assets. A moving asset may be a person, an animal, equipment (e.g., a forklift truck), goods, products or other items, including luggage, shipments such as boxes or containers, etc. A stationary asset may be anything equipped with sensors to monitor function and/or environmental conditions. Examples for such stationary assets include weather stations, pumps, pipelines, refrigeration equipment, air quality sensors, etc. The monitoring may be performed by a monitoring device (104) that is carried by the monitored asset or that is attached or installed on the monitored asset.

In one or more embodiments of the invention, a monitored asset (102) may further be controlled via the monitoring system (110). A monitoring device (104) may interface with the monitored asset (102) to, for example, activate or deactivate functions, switch modes, etc. If the monitoring device (104) is also used for sensing, a closed loop operation via the monitoring system (110) may be implemented. Based on sensed conditions, the monitored asset may be controlled in order to change the sensed conditions.

An access point (112), in one or more embodiments of the invention, is configured to communicate with the monitoring devices (104) of the monitored assets (102) via an Internet of Things (IoT) link (106). The access point may further interface with a hub (118), which may perform processing of the data received from the monitored assets via the access points, as further described below. In one or more embodiments of the invention, data gathered from the monitored assets is uploaded to a cloud environment (150), from where they may be accessible to users. Additionally or alternatively, the data may also be locally accessible via the hub or via the access point, as further described below. Each of the components of the system for monitoring assets is subsequently described in detail, with reference to FIGS. 2A-7.

Turning to FIG. 1B, an alternative configuration of a system for monitoring assets (110), in accordance with one or more embodiments of the invention, is shown. Unlike the system shown in FIG. 1A, the system of FIG. 1B includes multiple access points (112A, 112B). Each access point may have a limited range that may depend on the transmission power of the access point, but also on the transmission power of the monitoring devices (104) of the monitored assets (102). Accordingly, in order to cover larger environments (100) with monitoring services, multiple access points may be placed at different locations in the environment. FIG. 1B shows a primary access point (112A) and two secondary access points (112B). While the primary access point (112A) may directly interface with the hub (118), e.g., using a wired broadband link such as an Ethernet interface, the secondary access points may interface with the primary access point (112A) using a broadband link (120) such as a wireless local area network (WLAN) based on, e.g., the Wi-Fi standard. Using additional access points, distributed across the monitored environment (100), larger areas may thus be covered by the system for monitoring assets (110). Those skilled in the art will appreciate that various configurations of multiple access points are feasible without departing from the invention. For example, systems for monitoring assets may include any number of access points to monitor environments of any size. Further, multiple access points may directly interface with the hub (similar to the primary access point (112A)). Alternatively or additionally, multiple access points may increase the monitored area using a daisy chain configuration (i.e., tertiary access points may interface with the secondary access points, analogous to how the secondary access points interface with the primary access point). Further, in hybrid configurations, some access points may be daisy-chained, whereas other access points may directly interface with the hub. In one embodiment of the invention, an access point or multiple access points may be directly connected to the cloud, e.g., when a reliable connection to the cloud is continuously available.

Turning to FIG. 1C, another alternative configuration of a system for monitoring assets, in accordance with one or more embodiments of the invention, is shown. The system includes additional components that may facilitate the use of the monitoring system and/or provide additional features. In one embodiment of the invention, the broadband link (120) of the access point (112) is used to provide user access to the monitoring system (110). More specifically, user devices such as smartphones (128) or laptops (130) may connect to the access point (112) via the broadband link (120) in order to obtain monitoring data, to configure the monitoring system, etc. Data that is provided by the monitoring devices (104) and/or monitoring device data that has been previously collected, processed and/or stored by the hub (118) may be obtained via a hub/cloud platform, described in FIGS. 2A and 2B.

In one or more embodiments of the invention, the broadband link may further be used to interface additional devices with access points (112) of the monitoring system (110). In FIG. 1C, a drone (118) is shown, communicating with the access point (112) via the broadband link (120). The drone may further enhance the monitoring capabilities of the monitoring system (110). The drone may, for example, be equipped with a camera and/or other sensors and may be in contact with various access points, depending on the drone's current location in the monitored environment (100). The drone may further not necessarily be in continuous contact with an access point and may, instead, operate autonomously and may only require periodic contact with an access point. One or more drones (118) may be used to visually inspect environments. Multispectral cameras and/or mosaic photography may be used to monitor environmental conditions and/or activity in the monitored environment using additional analytics software.

Other sensors that rely on a broadband link (160) via one of the access points (112) may be part of the monitoring system as well. For example, cameras that are equipped with a Wi-Fi interface may be used to visually monitor certain areas of the monitored environment (100). Such cameras may include motion detection to detect activities including expected or desired activity, but also unexpected activity, such as intrusions. Additionally or alternatively, cameras may provide still photos, video clips or live videos and/or alarms based on a detection of certain events in the videos or photos. In addition, the broadband link (160) may be used for any other purposes such as voice over IP and/or for any other high data rate service.

In one or more embodiments of the invention, the monitoring system (110), using the IoT link (106), interfaces not only with the monitoring devices (104), but also with other sensors (122). The other sensors may perform environmental measurements such as air temperature, humidity, or may be used to monitor equipment such as pumps, storage tanks, pipelines, etc.

One or more embodiments of the invention further support additional sensing equipment in the form of peripheral sensors (124). A peripheral sensor may be used to acquire additional measurements that may not be obtainable by the monitoring device (104) itself. The peripheral sensors thus further extend the monitoring functionalities provided by the monitoring device (104). Any number of peripheral sensors (124) may be used in conjunction with a monitoring device (104). A local sensor link (126) may transmit the measurements obtained by the peripheral sensor (124) to the monitoring device (104), which may relay these measurements to one of the access points (112). An exemplary peripheral sensor is further discussed below, with reference to FIG. 5.

In one or more embodiments of the invention, the access point (112) is a two-tier access point equipped with a first tier broadband communication interface and a second tier narrowband communication interface. The first tier broadband communication interface provides the broadband link (120) and the second tier narrowband interface provides the IoT link (106). While the narrowband link may provide coverage of a comparatively large area at a reduced data rate that may be particularly suitable for monitoring devices (104) and other sensors (122), the broadband link may provide coverage of a comparatively smaller area at a higher data rate that may be suitable to serve other devices such as laptops (130), smartphones (128), or other broadband equipment, including drones (118), cameras (not shown), etc. The broadband link may further be used to establish a mesh with other access points, as previously shown in FIG. 1B. In one embodiment of the invention, the monitoring system includes a three-tier network that, in addition to the two tiers of the access point, includes a third tier formed by the local sensor link (126), as previously described.

FIG. 1C further shows a radio frequency identification (RFID) wand. The RFID wand may be used, in proximity of an RFID transmitter to read out basic information provided by the RFID transmitter. The RFID transmitter may be a component of the monitoring device (104) or of a peripheral sensor (124) and may provide static information such an ID. Consider, for example, the use of monitoring devices (104) to track luggage at an airport. Airport security may then be able to obtain the identity of luggage equipped with a monitoring device, using the RFID wand. The RFID wand (or stationary RFID readers) may further be used in other security and/or monitoring applications such as check-through scenarios at facility entries and exists, clock-in/clock-out applications, etc. The RFID wand may be equipped with a GPS unit, enabling obtaining a location at the time when RFID information is obtained from an RFID transmitter. Additionally or alternatively, the RFID wand may be equipped with an IoT interface enabling the RFID wand (132) to communicate with one or more access points (112) in order to obtain a location and/or to upload RFID information obtained from an RFID transmitter. Further, RFID wands, in accordance with one or more embodiments of the invention, may be equipped with a narrowband communication interface to establish a narrowband link (136), e.g., a Bluetooth link to another device such as a smartphone (128) or a laptop (130). The narrowband link may enable a user to access RFID data either spontaneously, e.g. as an RFID transmitter is read, or in bulk readouts, after a number of RFID transmitters have been scanned.

Turning to FIG. 1D, various options for interfacing the hub (118) with the computing devices in the cloud (150), e.g., using the Internet, are illustrated, in accordance with one or more embodiments of the invention. A wired backhaul uplink (140), a cellular backhaul uplink (142) and/or a satellite backhaul uplink may be used to interface the hub (118) with a cloud computing device, e.g., the cloud server (152). Alternatively, any other data connection, including any kind of point-to-point or multipoint connection that is at least temporarily available may be used as a backhaul link. In one embodiment of the invention, no backhaul link is used, i.e., the hub (118) is operating without an interface to the cloud (150), and therefore may only be accessed using local computing devices accessing the hub (118) via the access point (112), as previously described with reference to FIG. 1C. Alternatively, in one embodiment of the invention, no hub is used, i.e., the access point(s) may be directly connected to the backhaul link. Such a configuration may be suitable if the backhaul link is considered very reliable. Alternatively, if the backhaul link is considered less reliable, the hub may provide full or at least partial functionality while the cloud is not reachable.

The wired backhaul link (140) may be, for example, a wired Ethernet connection to an Internet service provider, a fiber-optic connection, a DSL Internet connection, a cable Internet connection, etc. Any type of wired data interface suitable to connect the hub to the cloud environment (150) may be used. The cellular backhaul link may be any type of cellular data connection such as a 3G, LTE or 5G data connection. Those skilled in the art will appreciate that any type of wired or wireless data link may be used as a backhaul link, without departing from the invention.

Turning to FIG. 1E, an exemplary radio signal coverage by a single access point (112), in accordance with one or more embodiments of the invention, is shown. As illustrated, a smaller region surrounding the access point receives broadband coverage (dashed circle), e.g., via the Wi-Fi signal of the access point. Within this zone, sensors that require a broadband link, e.g. cameras, may be installed. A larger region, surrounding the access point, receives narrowband coverage by the IoT link (108) (solid circle). While less data may be transmitted using the IoT link, data transmission using the IoT link may require less power and may be feasible over longer distances, in comparison to the broadband link. A monitoring device (104), which is typically battery-powered, therefore may use the IoT link rather than the broadband link. Those skilled in the art may appreciate that the areas that receive broadband and narrowband coverage depend on various factors, including the transmission power of the components involved in data transmissions, the types of antennas being used, terrain features, etc.

Turning to FIG. 1F, an exemplary radio signal coverage by multiple access points (112), in accordance with one or more embodiments of the invention, is shown. In the shown configuration, the access points are spaced such that there is significant overlap between the broadband coverage (dashed circles) provided by the different access points, but also between the narrowband coverage (solid circles) provided by the different access points. Using the set of access points, a coverage region (196) is entirely covered by narrowband signals of at least three access points. In one or more embodiments of the invention, overlap of narrowband coverage provided by multiple access points is desirable. Specifically, in a region where a sensor receives narrowband coverage by at least three narrowband signals (e.g., IoT signals), the signals of a monitoring device, received by at least three access points may be used to determine the location of the monitoring device, thus enabling, for example, location tracking of a monitored asset (102) equipped with a monitoring device (104). The location of a monitoring device may be determined using time difference of arrival (TDOA) methods. Accordingly, location tracking using TDOA methods may be performed in the coverage region (196) in which at least three access points may receive transmissions sent by the monitoring device. TDOA positioning may provide moderately accurate location information (e.g. with an accuracy of approximately 30-75 m), although the accuracy may deteriorate when the quality of the reception at one or more of the access points is poor. The measurement accuracy may, however, not be strongly affected by the presence of buildings and foliage. Alternatively, received signal strength indication (RSSI) positioning may provide location information with limited accuracy, (frequently no more accurate than approximately 75 m), and may allow positioning even under difficult conditions, e.g., when fewer than three access points are available. Further, if equipped with a global positioning system (GPS) receiver, the monitoring device's location may be determined using the GPS receiver. GPS positioning does not rely on the exchange of signals with access points and may thus be available anywhere, even outside the coverage region (196), although power requirements may be significantly higher when relying on GPS. Further, GPS signals may be blocked by structures, foliage, etc. However, the accuracy is typically higher than the accuracy of the TDOA and RSSI methods.

Accordingly, to enable energy efficient location determination in certain regions, access points may be strategically placed to have overlapping coverage regions, thereby not requiring the use of power consuming GPS positioning. In regions where TDOA based location services are desired, a dense grid of access points with a high degree of overlap may be installed to ensure that overlapping coverage is provided by at least three access points, whereas a sparse grid of access points may be installed in other regions. In these other regions, less accurate RSSI positioning may be used, or if an accurate location is required, GPS positioning may be used.

Turning to FIG. 1G, an exemplary radio signal coverage by multiple access points (112A, 112B), in accordance with one or more embodiments of the invention, is shown. To cover large areas effectively while allowing for extended battery life, up to years, access points may need to be deployed strategically to cover the desired monitored environment. The configuration shown in FIG. 1G uses a primary access point (112A) that directly interfaces with a hub (118) and provides an interface to the secondary access points (112B). Using the set of access points, a coverage region (198) is entirely covered by a narrowband signal (solid circles), while some areas are also covered by a broadband signal (dashed circles). In the exemplary configuration shown in FIG. 1G, the left part of the coverage region (198) is covered by sparsely placed access points, where broadband coverage regions are non-overlapping. In contrast, the right part of the coverage region (198) is covered by densely placed access points, where broadband coverage is overlapping, thus establishing a contiguous region with broadband signal coverage. Those areas may, thus, serve different purposes. For example, the left part may be used to monitor sensors that merely require a narrowband communication interface, e.g., weather sensors or monitoring devices for assets that do not require TDOA tracking. In contrast, the right part may be used for a drone surveillance that requires a continuous broadband signal. Those skilled in the art will appreciate that even though FIG. 1G shows the primary access point (112A) interfacing with a hub (118), the hub is not necessarily required. For example, the primary access point (112A) may directly interface with the cloud environment (150). Further, to provide coverage for larger areas and/or for larger numbers of assets to be tracked, additional access points, including primary and/or secondary access points and/or additional hubs may be deployed.

Turning to FIG. 1H, an exemplary monitoring system (110) that includes multiple network segments (192, 194), in accordance with one or more embodiments of the invention, is shown. Each of the network segments (192, 194), is equipped with a hub (118) and multiple access points (112), providing monitoring coverage. Alternatively, these network segments may be operated without hubs. Further, both network segments operate using the same RF plan, i.e., using the same transmission protocol and frequencies, further described with reference to FIGS. 6-12. Network segment 1 (192) is configured as a multitenant site, i.e., multiple customers (customers 1-4, site A) are served by the network segment. Consider, for example, a monitoring system (110) that is installed in a healthcare facility that is shared by multiple care providers. Assume that these care providers have in common that their patients require monitoring. Accordingly, the care providers agree to have a common monitoring system installed by a monitoring service provider that offers the monitoring as a service. Customer 1 is an assisted living provider with patients that may suffer from dementia and may therefore get disoriented within their environment. Staff therefore needs to be able to locate these patients. Customer 2 is a nursing home provider with patients that temporarily need support and may spontaneously need assistance, thus requiring localization of patients whenever they need assistance. Customer 3 is a mental health care center. Patients may be violent or may attempt to escape and therefore need to be monitored as well. Customer 4 is a drug rehabilitation center, where patients may also be violent and may try to escape and therefore also need to be monitored. Patients of the assisted living facility and the nursing home facility may be allowed to freely move between the assisted living facility and the nursing home facility. In contrast, allowed movement of patients of the mental health center and the drug rehabilitation center is strictly limited to areas within their respective facilities. The assisted living provider further operates a second assisted living facility on site B that is separate from site A, and that is covered by network segment 2 (194). Because network segments 1 and 2 belong to the same monitoring system, information about devices may be exchanged between the network segments. Accordingly, moving patients between site A and site B is straightforward. The scenario of FIG. 1H thus illustrates a multitenant, multisite monitoring system, in accordance with one or more embodiments of the invention. Those skilled in the art will appreciate that monitoring systems, in accordance with one or more embodiments of the invention, are fully scalable. For example, monitoring systems may include any number of sites, any number of customers and any number of patients or, generally speaking, assets to be monitored. Further, monitoring systems, in accordance with one or more embodiments of the invention, may be globally distributed. For example, sites A and B may be on different continents. Network segments may grow arbitrarily large, with any number of access points and/or monitoring devices. However, eventually a network segment with numerous devices may become congested, or the hub of the network segment may be overwhelmed by the incoming volume of data. In such a scenario, the network segment may be split into two or more separate network segments, each with its own hub and access points.

Turning to FIG. 2A, a hub-cloud configuration of a system for monitoring assets, in accordance with one or more embodiments of the invention, is shown. The hub-cloud configuration includes the hub (210), the cloud (230), and the user application (250). A hub/cloud platform (270), jointly executing on the hub (270) and in the cloud (230) in a distributed manner, provides back end-support for various components of the monitoring system (110), as further described with reference to FIG. 2B. A user application (250) may be relied upon by a user to access the hub/cloud platform (270) via the hub (210) and/or via the cloud (230). Each of these components is subsequently described.

Services, made available through the hub/cloud platform (270) may include, for example, providing data, gathered by the monitoring system (110), to the user, enabling the user to configure the monitoring system, etc. The hub/cloud platform (270) may be accessed by a user using the user application (250), which may be executing on a computing device such as a smartphone or a laptop. The user application (250), thus, may provide a user interface configured to enable the user to access the hub/cloud platform, and to receive notifications on critical events. The user application may include for example, alert displays, status messages, data visualization capabilities, control and configuration capabilities, etc. The user application may further provide data entry fields (e.g., to configure the monitoring system), specialized control interfaces (e.g., to control a drone), voice over IP (VoIP) and/or push to talk interfaces and other communication interfaces that are supported by the broadband links provided by the access points. Alternative implementations of the user application (250) may operate on other devices, e.g., on an audio alert device.

Depending on whether the user application (250) accesses the hub/cloud platform (270) via the hub (210) or via the cloud (230), the user application (250) may interface with the hub/cloud platform via the app service (212) of the hub (210) (e.g., using a smartphone's Wi-Fi interface) or via the app service (232) of the cloud (230) (e.g., using the smartphone's LTE interface). When a user is on-site, e.g., directly connected to an access point using a Wi-Fi link, accessing the hub/cloud platform (270) may be particularly low-latency because the interaction of the user's computing device with the hub is local.

The hub (210) includes a computing device configured to perform at least some of the steps described with reference to the flowchart of FIG. 8, and one or more communication interfaces that enable the hub to interface with one or more access points (112), the cloud (230), and the computing device that executes the user application (250). The computing device of the hub may be, for example, an embedded system that includes all components of the computing device on a single printed circuit board (PCB), or a system on a chip (SOC), i.e., an integrated circuit (IC) that integrates all components of the computing device into a single chip. The computing device may include one or more processor cores, associated memory (e.g., random access memory (RAM), cache memory, flash memory, etc.), one or more network interfaces (e.g., an Ethernet interface, a Wi-Fi interface, a Bluetooth interface, etc.), and interfaces to storage devices, input and output devices, etc. The computing device may further include one or more storage device(s) (e.g., a hard disk, an optical drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, flash memory, etc.), and numerous other elements and functionalities. In one embodiment of the invention, the computing device includes an operating system that may include functionality to execute the methods further described below. Those skilled in the art will appreciate that the invention is not limited to the aforementioned configuration of the computing device.

The cloud (230), in accordance with one or more embodiments of the invention, may be formed by multiple/many networked computing devices. These computing devices may be geographically and organizationally distributed in any way. For example, some of these computing devices may be located in a data center, whereas other such computing devices may be individual physical or virtual servers. An exemplary computing system, as it may be used in the cloud, is shown in FIG. 13. One or more of the computing devices may host the hub/cloud platform (270), analogous to how the hub/cloud platform is hosted on the hub (210). While the components of the hub/cloud platform that are executing on the hub (210) and that are executing on a computing device in the cloud (230) may operate separately, they are interconnected, e.g. via the backhaul link (140), thus enabling synchronization between these components. Accordingly, the same information may be available, regardless of whether the user application connects via the hub (210) or via the cloud (230). Temporary discrepancies may exist though, e.g., during times when the backhaul link (140) is interrupted, and a synchronization is therefore unavailable. Further, because additional, e.g., more complex, data processing may be performed in the cloud, additional data, resulting from the additional processing, may be available when connecting to the hub/cloud platform (270) via the cloud. Such data may, however, also be available via the hub (210), if they are synchronized to the hub (210) via the backhaul link (140). The cloud may run multiple instances of the hub/cloud platform in order to support the load of many sites and/or many users. Depending on the configuration of the hub/cloud platform, incoming data, i.e., data received from a particular hub, a particular device, a particular site, or a particular customer, may be distributed between multiple instances, or may be consistently assigned to the same instance, using, e.g., a consistent hash ring configuration.

Those skilled in the art will recognize that other configurations that deviate from the configuration introduced in FIG. 2A may exist, without departing from the invention. For example, in monitoring systems (110) that do not include an interface to the cloud (230), the hub/cloud platform (270) may solely execute on the hub. In such a scenario, the hub is configured to “self-backhaul”, i.e., the hub may collect and consolidate monitoring device data and may perform some or even all of the processing that would otherwise be performed in the cloud. Similarly, in monitoring systems in which the access points (112) directly interface with the cloud (230), the hub/cloud platform (270) may solely execute in the cloud. All functionality, even functionally that would typically be provided by the hub, in this case may be provided in the cloud. The configuration of the monitoring system, with or without hub, in one or more embodiments of the invention, may be transparent, i.e., monitoring devices or other devices may operate in the same manner, regardless of the presence of a hub. Similarly, a user may experience the same monitoring system, whether the hub is present or not.

Turning to FIG. 2B, additional details of the hub/cloud platform (270) are shown. In one or more embodiments of the invention, the hub-cloud platform is organized in layers. Core services (276) provide basic functionalities such as data storage, network, and messaging. On top of the core services (276), the IoT services (274) provide services that are specific to IoT networks, but that are not necessarily specific to a particular application, such as the use in a healthcare environment. The IoT services may thus include, for example, location services (e.g., GPS, TDOA or RSSI based), IoT network services and configurations, etc. The topmost layer includes application and/or environment-specific services (272). These services, in case of a healthcare environment may include, for example, analysis of patients' vital signs, a patient location tracking interface, etc. In contrast, in case of an oilfield environment, these services may include, pipeline operation analytics. Additional application-specific layers may be added, without departing from the invention. The hub/cloud platform is, thus, modular, allowing adaptation to many applications, depending on the services selected for execution on the hub/cloud platform.

These services, in accordance with one or more embodiments of the invention, may be available through the hub (210) and/or through the cloud (230). A synchronization may be performed between the services executing in the cloud and the services executing on the hub, thus maintaining consistency between the hub and the cloud. As long as a communication link (e.g., the backhaul link (140)) is available, the data available through the hub and through the cloud may be identical. However, if the communication link temporarily becomes unavailable, data that is accumulated on the hub may not be available through the cloud. A synchronization may be performed once the communication link is restored, to update the cloud with the data available on the hub. Accordingly, a consistent data view is available via hub and cloud, in accordance with one or more embodiments of the invention.

Turning to FIGS. 3A and 3B, access points (300), in accordance with one or more embodiments of the invention, are shown. In FIG. 3A, the general design of an exemplary access point is shown, and in FIG. 3B, the architecture of the access point is illustrated. The exemplary access point shown in FIG. 3A includes a broadband interface antenna (302), a GPS antenna (312), an IoT radio antenna (322) and solar cells (332). As shown in FIG. 3B, the access point further includes a broadband interface (304), a GPS interface (314) and an IoT radio interface (324).

The broadband interface (304) uses the broadband antenna (302) in order to send and receive broadband data transmissions when in contact with, e.g., other access points, as illustrated in FIG. 1B and/or with other devices such as smartphones, laptops, cameras and/or drones that are also equipped with broadband interfaces. The broadband interface may support mesh, point-to-point and multi-point connections. The broadband interface may be based on the Wi-Fi standard, using, e.g., the 2.4 and/or 5 GHz radio bands. Alternatively, the broadband interface may be a cellular data interface, e.g., a 3G or 4G/LTE or 5G interface, or any other wireless data interface, without departing from the invention.

The GPS interface (314) uses the GPS antenna (312) to obtain position signals from the global positioning system or from alternative satellite navigation services. The position signal enables the access point to accurately determine its own position. In one or more embodiments of the invention, the GPS interface further obtains an accurate time base that may be used by the access point to perform localization tasks using TDOA methods, as further described below.

The IoT radio interface (324) uses the IoT radio antenna (322) to communicate with one or more IoT devices such as the monitoring devices (104). The IoT interface may be based on a low power wide area network standard such as, for example, LoRa. The resulting narrowband link is particularly suitable for communications between the access point and the monitoring devices or other sensors, due to its low power requirements, long range, and its ability to interface with many monitoring devices and/or other devices. In one or more embodiments of the invention, the IoT radio interface (324) supports communication protocol extensions implemented on top of an existing IoT communication protocol to provide scheduled communications and timing beacons as further discussed below, with reference to FIGS. 6-12.

In one or more embodiments of the invention, the access point (300) further includes an access point processing engine (342). The access point processing engine may handle the processing of data received from monitoring devices and other sensors, and may coordinate the uploading of the processed data to either the hub or to the cloud. The processing of data may involve, for example, data aggregation, data filtering, data fusion, data compression and/or data encryption.

In one or more embodiments of the invention, the access point (300) further includes a monitoring device localization engine (344). The monitoring device localization engine may be used to determine the locations of monitoring devices that are within the coverage region of the access point. The localization may be performed, for example, using TDOA methods. Using the TDOA method, triangulation, based on the differences in time delay of a data transmission by a monitoring device, received by at least three access points, may be performed. The monitoring device localization engine of an access point may use this time delay information to determine the location of the monitoring device responsible for the data transmission. Because TDOA methods depend on the availability of an accurate time base to the monitoring devices whose location is to be determined, communication protocol extensions that enable dissemination of an accurate time base to the monitoring devices via the IoT link, as discussed with reference to FIGS. 6-12, are used by the access point. Alternatively, the monitoring device localization engine may extract the location of a monitoring device from a message provided by a sensor equipped with a GPS unit. Further, the monitoring device localization engine may also determine a location of a monitoring device based on the signal strength of a data transmission obtained from the monitoring device, using the RSSI method. Those skilled in the art will appreciate that, although the method performed by the monitoring device localization engine is described with regard to monitoring devices, any device that is equipped with an IoT interface, and that is capable to communicate with the access points, may be localized by the monitoring device localization engine.

The access point processing engine (342) and the monitoring device localization engine (344) may be software executing on a computing device (not shown) of the access point (300). The computing device of the hub may be, for example, an embedded system that includes all components of the computing device on a single printed circuit board (PCB), or a system on a chip (SOC), i.e., an integrated circuit (IC) that integrates all components of the computing device into a single chip. The computing device may include one or more processor cores, associated memory (e.g., random access memory (RAM), cache memory, flash memory, etc.), and interfaces to storage devices, input and output devices, etc. The computing device may further include one or more storage device(s) (e.g., a hard disk, an optical drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, flash memory, etc.), and numerous other elements and functionalities. In one embodiment of the invention, the computing device includes an operating system that may include functionality to execute the methods further described below. Those skilled in the art will appreciate that the invention is not limited to the aforementioned configuration of the computing device.

In one or more embodiments of the invention, the access point further includes a power system that may include the solar cells (332), a battery (334) and a charge controller (336), powering the access point. The battery may be deep-cycle capable to guarantee continued operation at night or under cloudy conditions when power provided by the solar cells is insufficient. The solar cells may be dimensioned to enable powering the access point while also recharging the battery. Alternatively, the access point may be powered externally, e.g., using power over Ethernet (PoE) or using a dedicated power input. The charge controller in combination with the access point processing engine (342) may provide charging, battery status and power consumption analytics, enabling power management of the access point. A direct current (DC) power and data over DC power link may be used to power the access point by the power system, but also to enable the charge controller to communicate status information (such as battery level, temperature, etc.) to the access point.

FIGS. 3C-3G show an exemplary access point & hub assembly, in which a hub and an access point are installed in combination on a pole. The assembly (390) includes the access point (300), an antenna pole (392), solar cells (332) and a hub & battery box (394). Alternatively, the access point & hub assembly may be powered by AC line voltage, either continuously or intermittently. In this case, the access point & hub assembly may not be equipped with solar cells, but may instead include AC to DC conversion circuits to power the access point & hub assembly and/or to charge the battery. While the access point (300) is installed near the top of the antenna pole (392), for improved reception, the hub (318) may be housed in the hub & battery box (394), together with the battery (334) and the charge controller (336) near the base of the antenna pole (392), thus facilitating access. The access point (300) may be connected to the hub (318), using an Ethernet cable, which may also power the access point using PoE. In one embodiment of the invention, the antenna pole (392) can be pivoted into a horizontal position, thereby facilitating installation and servicing of the access point (300) near the top of the antenna pole as illustrated in FIG. 3G

FIG. 4 shows a monitoring device (400) in accordance with one or more embodiments of the invention. A monitoring device may be used to monitor an asset, including the asset's location and other variables, as subsequently discussed. The monitoring device may be equipped with a mounting or attachment element that is application specific. For example, in industrial or commercial applications, the monitoring device may be permanently bolted to an equipment to be monitored. In animal applications, the monitoring device may be attached using an ear pin or a collar. Further, in human applications, the monitoring device may be designed as a wristband, an ankle monitor or as a unit that can be worn in a pocket. The monitoring device may further be installed on a hard hat, as it may be worn by workers in the oil & gas, construction, refining, and other industries. In such applications, the monitoring device may be a tag that is attached to the front or the back of a hard hat. In automotive applications, the monitoring device may be a tag that is hanging from the rear view mirror. If monitoring devices are used to track the location, temperature and/or fill level of portable tanks, such as propane tanks, these monitoring devices may be equipped with mounts to permanently or temporarily attach the monitoring devices to these tanks. Those skilled in the art will appreciate that the monitoring device is suitable for many applications and may thus be adapted to include mounting elements as needed. The monitoring device may further be equipped with an RFID tag. The RFID tag may electronically store information such as a unique asset-specific identifier. The RFID tag may be passive, i.e., not requiring a battery, and may be electromagnetically powered by a nearby reader, e.g., the RFID wand (132), previously discussed in FIG. 1C. The monitoring device may further include active components, including one or more external sensors (406). Data from these sensors may be transmitted to one or more of the previously introduced access points using the IoT link. The external sensors may be physiological sensors (e.g., blood pressure or heart rate sensors) or sensors for environmental variables such as temperature, humidity, etc. These sensors may have a wired or optical interface (e.g., infrared) to the monitoring device.

In one or more embodiments of the invention, the monitoring device (400) includes an IoT transceiver (410). The IoT transceiver (410) may be configured to communicate with one or more access points, using an IoT protocol such as LoRa. Communications may include, but are not limited to, the receiving of a time base from one or more access points, the receiving of a configuration, the receiving of a firmware, the sending of monitoring device data, e.g., data previously collected by one of the subsequently described sensors, and/or the sending of monitoring device status data, such as errors, battery level, etc. The activity of the IoT transceiver may be optimized to minimize power consumption. For example, the IoT transceiver may be in a deep sleep mode whenever no transmission of data is required.

In one or more embodiments of the invention, the monitoring device (400) further includes a processor (412). The processor may gather data from one or more of the subsequently described sensors and may process the data for transmission via the IoT transceiver. The transmissions may be performed as specified by the IoT communication protocol overlay, further described with reference to FIGS. 6-12, to minimize communication inefficiencies such as collisions with data sent by other monitoring devices and/or to conserve battery power. The organization of the data as instructed by the IoT communication protocol overlay may be performed by the processor (412). The processor may be a microcontroller unit (MCU) that may be implemented as a system on a chip (SOC). The processor may be selected based on computational requirements and battery life requirements.

In one embodiment of the invention, the monitoring device (400) may include a GPS receiver (414), sensing devices (416) and/or a peripheral sensor transceiver (418). The GPS receiver, if present, may be used to determine the location of the asset when other, more power efficient, methods for determining the location (such as TDOA and/or RSSI) are not available, e.g., when the number of access points that are simultaneously in communication with the monitoring device is insufficient or the resulting location data is not sufficiently accurate. When not in use, the GPS receiver may be in a deep sleep mode or completely powered down. One or more sensing devices (416) may be used to obtain measurements from the monitored asset (102) or the surrounding environment. These sensing devices may include, but are not limited to, pressures sensors for gas and/or liquid applications, air or gas leak sensors, fill level sensors e.g., for storage tanks, valve position sensors (e.g., to monitor the function of valves), weight and/or strain sensors (including bending, torsion, etc.), and temperature sensors, spectroscopy sensors (to perform chemical analyses beyond basic gas sensing), energy usage or delivery sensors, etc. The one or more sensing devices (416) may be interfaced with the processor (412) using digital and/or analog interfaces.

In one or more embodiments of the invention, the monitoring device (400) is further equipped with a control interface (not shown). The control interface may include analog or digital outputs, including communication bus systems, and/or relays, motors, or any other equipment that may be used to control functions of the monitored asset (102) and/or other components in vicinity of the monitored asset. Those skilled in the art will appreciate that the control interface may be used to control any function of the monitored asset or functions of other components in the monitored environment.

The optionally present peripheral sensor transceiver (418), in one embodiment of the invention, establishes a data link to one or more peripheral sensors, such as the sensor discussed below, with reference to FIG. 5. The data link may be very low power, limited to a range of only, for example, three to six feet. A transmission frequency may be in a range suitable to penetrate tissue. Highly power efficient circuits (such as class C amplification) may be used to minimize power consumption, in particular on the side of the peripheral sensor, which may need to operate using small batteries. The data link may use a communication protocol analogous to the protocol further described below with reference to FIGS. 6-12, although a simplified version (e.g., fewer communication slots) may be provided.

In one or more embodiments of the invention, the components of the monitoring device are battery powered. The battery (424) may be a rechargeable or a non-rechargeable battery that may or may not be replaceable, selected to power the components of the monitoring device for a specified duration, e.g., for multiple months or years. If the battery is rechargeable, a power or charge controller (426) may control the charging of the battery, e.g., from solar cells (422) or other external power sources, such as inductively provided power. The power/charge controller may further communicate battery status information to the processor (412). This status information may be communicated to an access point, e.g., when a low battery level is detected. In addition, the battery level may directly govern the operation of the monitoring device. For example, when a low battery level is detected, the communication frequency may be reduced, certain sensors may be deactivated, etc. External power supplies may be used, e.g., if the monitoring device is stationary.

FIG. 5 shows a peripheral sensor, in accordance with one or more embodiments of the invention. The peripheral sensor (500) may include a sensing instrumentation (502), electronic circuits (510), an antenna (522) and a battery (532). Depending on the environment for which the peripheral sensor (400) is designed, the peripheral sensor may be hermetically sealed e.g., to prevent fluids from entering the sensor. The sensing instrumentation may include, but is not limited to, pressures sensors for gas and/or liquid applications, air or gas leak sensors, fill level sensors e.g., for storage tanks, valve position sensors (e.g., to monitor the function of valves), weight and/or strain sensors (including bending, torsion, etc.), and temperature sensors, spectroscopy sensors (to perform chemical analyses beyond basic gas sensing), energy usage or delivery sensors, etc. Consider, for example, the application of monitoring devices and peripheral sensors in mining, refining or industrial environments. The peripheral sensors may include gas sensors, configured to provide early hazard warnings to workers, on an individual basis. Alternatively, in another scenario, a monitoring device is used to monitor the fill level of a storage tank. A peripheral sensor, interfacing with the monitoring device, may further monitor a pump to monitor vibration, energy consumption, including static and transient energy consumption, and/or to control the pump, and thus, indirectly, the fill level of the storage tank. Those skilled in the art will appreciate that the peripheral sensor, when equipped with a control interface, may be used to control any function of the monitored asset or functions of other components in the monitored environment.

The electronic circuits (510), in accordance with one or more embodiments of the invention, include a processor (504) and a peripheral sensor transceiver (506). The processor (504) may be a particularly energy-efficient unit such as a microcontroller that may be implemented as a system on a chip (SOC). The processor may be selected based on computational requirements and battery life requirements. Temporarily used peripheral sensors may only need to remain operative for a few days, whereas permanently installed versions of the peripheral sensor may need to be operational for the lifetime of the monitored asset. The peripheral sensor transceiver (506) is configured to interface the peripheral sensor with the monitoring device (400) over a short distance using a low-power signal with minimal power requirements, in order to communicate the collected peripheral data to the monitoring device, from where it may be forwarded to an access point.

The battery (532) may be a rechargeable or a non-rechargeable battery, selected to power the components of the peripheral sensor for a specified duration, ranging from a few days to the lifetime of the asset. If the battery is rechargeable, a power controller (534) may control the charging of the battery from inductively provided power. The power controller may further communicate battery status information to the processor (504). This status information may be communicated to an access point, e.g., when a low battery level is detected. In addition, the battery level may directly govern the operation of the peripheral sensor. For example, when a low battery level is detected, the communication frequency may be reduced, certain sensors may be deactivated, etc.

In one or more embodiments of the invention, a communication protocol overlay is used to enable the previously described system and system functions. By applying a protocol extension (the communication protocol overlay) to a base IoT system protocol, the extended IoT protocol provides additional functionality while maintaining compatibility with the base IoT system. The communication protocol overlay establishes the previously described IoT links between access points and monitoring devices and/or other sensors or devices and is designed to serve various purposes. For example, it enables the distribution of an accurate time base by an access point to monitoring devices or other devices communicating with the access point. In one or more embodiments of the invention, the IoT communication protocol overlay further establishes rules for data exchanges in the form of frequency bands and time slots to be used for communications, to reduce or eliminate collisions that may otherwise occur when multiple monitoring devices attempt to simultaneously transmit data. In addition, the IoT communication protocol overlay may enable energy efficient operation of access points and devices that are communicating with the access points. The details of these functionalities are further discussed below.

In one or more embodiments of the invention, the IoT communication protocol overlay may be used to extend existing beacon-based protocols such as LoRa, or SigFox, but also other protocols such as the 802.11 Wi-Fi protocol. Generally speaking, the IoT communication protocol overlay may be applied to any communication protocols that are based on time-division multiple access (TDMA), frequency-division multiple access (FDMA), or multi-frequency time-division multiple access (MF-TDMA) methods. In one embodiment of the invention, the IoT communication protocol overlay is placed on top of the data link layer (layer 2 of the open systems interconnection (OSI) model).

Subsequently, an MF-TDMA implementation of the IoT protocol extension is discussed. FIG. 6 shows the use of the IoT communication protocol overlay applied to IoT links (640) for communications between access points (610, 610.A.N-1, 610.A.N, 610.C) and monitoring devices (620.A-620.C). The communication protocol overlay may, however, also be used for to establish a local sensor link (650) between a monitoring device (620) and a peripheral sensor (630). The communication between peripheral sensors and monitoring devices may allow the use of a scaled-down version of the communication protocol overlay. For example, the data volume to be transmitted may be significantly less, the transmission distances may be rather short, etc. In addition, the use of the IoT communication protocol overlay may affect the communications between access points (610.A.N, 610.A.N-1, 610.C, 610) via broadband links (660).

Turning to FIG. 7 an IoT communication protocol overlay (700) based on a superframe (702) and frames (704) is established. In one or more embodiments of the invention, the IoT communication protocol overlay (700) is implemented on top of the LoRa WAN Class B protocol, thereby enhancing the LoRa WAN Class B protocol to include synchronous uplinks and other features, as further described below (LoRaWAN™ is a protocol, described by the LoRaWAN Specification. The LoRaWAN 1.1 Specification by the LoRa Alliance is hereby incorporated by reference in its entirety. Those skilled in the art will recognize that the proposed protocol extension may, however, also be implemented on top of other communication protocols, without departing from the invention.

Using the protocol extension, IoT devices (such as the monitoring devices) that are compatible with the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, are scheduled unique time and frequency communication slots, based on the bandwidth and IoT data rate needs of the IoT devices and/or their services that are published with the system at the time the IoT devices are activated. Further, asynchronous services can be supported on one or more separate frequency channels processed by the access point such that both standard IoT protocol devices and IoT communication protocol overlay-capable devices are supported.

Continuing with the discussion of the IoT communication protocol overlay (700), a superframe (702) represents one network period, during which all periodic network functions are completed, in accordance with one or more embodiments of the invention. In other words, upon completion of a superframe (702), all participating IoT devices (i.e., the subscribers) may have had an opportunity to communicate their data, as initially defined when the IoT devices were activated. Each superframe is subdivided into frames (704).

Each frame may start with a simultaneous beacon transmission (712) from the access points that synchronizes all the network devices. Each access point may be synchronized using a GPS time of a GPS receiver. Each subscriber (e.g. a monitoring device) in the network may be synchronized by receiving the beacon transmission. Because a subscriber may experience clock drift over time, the beacon may be transmitted at the start of each frame to maintain network synchronicity. While a subscriber may contain a GPS receiver, it is frequently battery-prohibitive to repeatedly activate the GPS receiver. The built-in GPS receiver of the subscriber may, however, be used occasionally to resynchronize when the subscriber is forced to enter “beacon-less” operation. A beacon-less operation may become necessary if the subscriber is unable to receive the beacon (e.g., in a network deadspot). Under such circumstances, the subscriber may activate the internal GPS unit to obtain a GPS time that allows the subscriber to retain network synchronicity through the use of its own GPS receiver. The subscriber may then seamlessly rejoin the network once it leaves the network deadspot.

A beacon transmission may include or may be followed by a communication of various data to the subscribers (e.g. the monitoring devices) within the range of the access points. The data may include a precise time base that the access point may have obtained from its GPS unit. The data may further include a specification of the IoT communication protocol overlay, e.g., network management messages informing the subscribers that are supposed to communicate with the access point of the timing and frequency of communication slots (716) assigned to them for data transmission. Only one subscriber may transmit in its respective time slot and frequency slot at a time. While the unique time and frequency slot assignments may be made at the time when a subscriber joins the network, these slot assignments may be changed by central network management. The assignment may be performed for an individual subscriber, for multiple, or for all subscribers. In one embodiment of the invention, a bit may be appended to the end of the beacon transmission to indicate whether there are network management messages that follow the beacon. A subscriber may thus conserve energy by not listening for additional messages, unless the bit is set. In the exemplary IoT communication protocol overlay of FIG. 7, the network management messages are bundled into the beacon (712).

In the exemplary IoT communication protocol (700), the beacon hops frequency channels prior to each beacon transmission. For three frequency channels, the first beacon may be on channel 1, the second beacon on channel 2, the third beacon on channel 3, and the fourth beacon again on channel 1. The order of the frequency hopping and the number of frequency channels may be altered, without departing from the invention.

Subsequently, data transmission communication slots may be opened for uplink from the network subscribers. These uplinks may form the payload that is sent up to the network server for processing. The payload may contain sensor data, GPS data and/or status messages.

In the exemplary IoT communication protocol overlay (700) of FIG. 7, a frame includes 24 communication slots. Groups of eight communication slots may be simultaneously transmitted using different frequencies. Communication slots may be assigned in any way. For example, a communication by a particular subscriber may be performed using a single assigned communication slot or, if necessary, multiple communication slots that may occur in parallel at different frequencies (channels) and/or consecutively. No communication slot may be assigned to multiple devices to prevent communication collisions. In total, the exemplary IoT communication protocol overlay (700) of FIG. 7 provides 72 communication slots (716). Accordingly, up to 72 individual communications may be performed in a single superframe (702). If these 72 communications are insufficient to serve all subscribers, the protocol overlay may be modified in various ways without departing from the invention. For example, a superframe may be configured to include more than three frames. Additionally or alternatively, a frame may include more than three consecutive communication slots, and/or additional frequencies (channels) may be used to allow simultaneous transmission of additional communication slots. The same IoT communication protocol overlay may be used by all access points across a site.

In one embodiment of the invention, the IoT communication protocol overlay is implemented on top of the LoRa WAN Class B protocol. A superframe may have a duration of 640 seconds and may consist of 5 frames, each with a duration of 128 seconds. Each frame may include 400 sequential communication slots, in eight separate frequency bands, resulting in total of 3,200 communication slots per frame. The duration of the beacon may be 2.12 seconds, and the duration of the beacon guard time may be 3 seconds. Those skilled in the art will appreciate that IoT communication protocol overlays may deviate from this exemplary protocol overlay in any way, without departing from the invention.

In one or more embodiments of the invention, not all channels that are available in the underlying IoT communication protocol are also used by the IoT communication protocol overlay. Channels that are not made available may be used to support devices that are not designed to work with the IoT communication protocol overlay, but that are capable of communicating using the underlying IoT protocol.

The final portion of the frame (beacon guard time (714)) may be reserved for other network functions. For example, this portion of the frame can be used for high-priority communications or for large data downlinks to the subscriber(s).

An example of a high-priority communication is the network server requesting an immediate location update from a subscriber, in accordance with an embodiment of the invention. While the subscriber would normally only transmit this information during its assigned data transmission communication slot (which may be several frames away), it may immediately transmit its location in the next reserved data transmission communication slot(s) if it receives an immediate location request from the network server (via the network management messages earlier in the frame).

An example of large data downlink to the subscriber is an over-the-air (OTA) firmware update, in accordance with an embodiment of the invention. Firmware updates are orders of magnitude larger than the typical payload size, in an IoT network. To facilitate downlink of such a large payload, the firmware update may be broken up into pieces and each piece may be transmitted in a separate frame. Each subscriber may grab pieces of the firmware update during each frame. In addition, after all the pieces have been transmitted once, this process may be repeated. In this way, any subscriber that missed a piece of the firmware update during the initial transmission can download the missed piece during the next round. The transmissions of the firmware may be repeated for any number of rounds. This “carousel” structure may improve the reliability of downlinking large data payloads to subscribers.

The beacon guard time (714), may further enable other IoT devices that are merely capable of communicating using the underlying IoT communication protocol, but not the IoT communication protocol overlay, to communicate, while devices that use the IoT communication protocol remain silent.

Those skilled in the art will appreciate that IoT communication protocol overlays, in accordance with one or more embodiments of the invention, are not limited to the exemplary IoT communication protocol overlay illustrated in FIG. 7. For example, an IoT communication protocol overlay may be implemented on top of any underlying data communication protocol, whether asynchronous or synchronous. Further, the IoT communication protocol overlay may be implemented for any number of channels (frequencies), a superframe may include any number of frames, and a frame may include any number of communication slots, without departing from the invention.

Turning to FIG. 8, an exemplary frame of the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, is shown. The exemplary frame starts with the transmission of a beacon. In one embodiment of the invention, the entire beacon downlink time is 2.12 seconds. However, the actual beacon time may be only 150 ms. The remaining time may be assigned to downlink transmissions to either specific subscribers to groups of subscribers, or to all subscribers. As previously described, the beacon may be relied upon by the subscribers in order to synchronize. The beacon may be followed by a brief margin, during which no transmission occurs. The margin may be used to buffer communication timing inaccuracies. Next, three downlink transmissions are performed, each followed by a margin. In one embodiment of the invention, 19 downlink slots are available. Fewer or more downlink transmissions may be performed, without departing from the invention. One or more of these downlink transmissions may include network management messages, e.g., configuration data for assigning communication slots to the subscribers. In one or more embodiments of the invention, the downlink transmissions are a component of the beacon transmission or directly follow the beacon transmission. The downlink transmission may be followed by uplink transmissions, organized in subsequent uplink transmission slots, each followed by a margin. Any number of uplink transmission slots may be included in a frame. A single uplink slot may be used by a particular subscriber, but not by multiple subscribers. An uplink data transmission may include, for example, sensor data. If a single uplink slot is insufficient for uploading data to one or more access points, multiple uplink slots may be assigned to the subscriber. How many uplink slots are assigned to a particular subscriber, and in what configuration (e.g., which channel), may be specified in a network management message. The uplink transmissions may be followed by a period of time during which no transmissions are scheduled, using the IoT communication protocol overlay. This “reserved” beacon guard time may be available for transmissions by legacy devices or commercial off-the-shelf devices, i.e., devices that do not support the IoT communication protocol overlay, but that are capable of using the underlying IoT communication protocol. In other words, access points may be able to receive communications from these legacy devices, while the subscribers are “silent”. The beacon guard time may further be used for high-priority transmissions by subscribers and/or for large data downlinks, as previously described.

For simplicity, the exemplary frame shows uplink communication slots for a single frequency (channel), as uplink communications are sequentially performed on that channel by one or more subscribers. Those skilled in the art will appreciate that multiple uplink communications may, however, be performed in parallel, without departing from the invention.

Turning to FIG. 9, a communication slot reassignment in the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, is shown. An assignment of a particular frequency and a particular time slot to a subscriber is not necessarily static. Network management may communicate changes in the assignment of frequencies and time slots to subscribers using the network management downlinks. The resulting frequency and time slot agility may be particularly beneficial in environments in which there is interference in specific frequency channels and/or during particular time periods. In one or more embodiments of the invention, an interleave of the frequency and time slot per superframe (or Nth superframe) is implemented. After, for example, completion of a superframe, each subscriber shifts one slot in frequency and/or time. In doing so, increased robustness to interference is built into the IoT communication protocol extension. A subscriber that had been assigned a “bad” time and/or frequency slot may not consistently experience interference as new frequencies and/or times are periodically assigned. FIG. 9 illustrates this concept in an example of three consecutive superframes. A continuous external interference prevents communication on one of the channels. After completion of a superframe, an exemplary communication slot “T1” is shifted to an adjacent time and frequency slot. Although a transmission of data using T1 fails in the first superframe because T1 is affected by the interference, subsequent transmissions using T1 are successful due to the shifting of T1. Although not shown in FIG. 9, other communication slots may be similarly shifted. Accordingly, a scheme that systematically rotates or shifts all communication slots results in only temporary interference with a transmission using a particular communication slot, even if the interference is permanently present.

The following use case scenarios are intended to provide example of possible uses of the IoT communication protocol overlay, in accordance with one or more embodiments of the invention. The use case scenarios are for illustrative purposes only, and the IoT communication protocol overlay is not limited to the applications discussed below.

Use Case I: Power Savings by an Access Point, Using the IoT Communication Protocol Overlay

Turning to FIG. 10, a first power saving scheme implemented using the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, is shown. Power savings may be particularly beneficial if an access point is solar and/or battery-powered. The subsequently described IoT subscriber scheduling may limit the use of communication time and/or frequency slots to limit energy consumption. In one embodiment of the invention, the IoT radio interface of an access point is fully powered, including all transmit and receive frequency channel transceivers during the transmission of each superframe or frame beacon and remains on for the scheduled subscriber communications time/frequency slots. Once the communications have been completed, the IoT radio interface may be placed in a low power mode in which only one or a few channels remain operative to enable asynchronous communications, thus allowing for new subscribers to join and/or allowing legacy devices to communicate with the access point(s), as illustrated by the AP IoT power cycle shown in FIG. 10. The full power phases of the AP IoT power cycle overlap with the IoT super frame & frame beacons and with the active IoT sensor communication slots. The low power phases, during the remaining time, conserve energy by shutting down the majority of the communication channels, while still allowing communications on a few remaining channels. Further, FIG. 10 also illustrates power savings across a series of access points that relay data obtained from a monitoring device to a primary access point using broadband or backhaul links. Such a configuration is shown, for example, in FIG. 6, where data, originally received from a monitoring device, is transferred from access point to access point using backhaul links (N . . . N-2). Initially, data represented by two blocks are transferred from access point N to access point N-1 using backhaul link N. At access point (N-1), additional data (which may have been obtained from another monitoring device), are added to the data, now represented by four blocks, which are transferred to access point N-2 using backhaul link N-1. Each of the involved backhaul links is powered only when required for the data transmissions, as indicated in FIG. 10. While those data transmissions shift in time, due to the receive/sent operations performed by each access point when relaying the data, each access point operates in a power-efficient manner by only powering the backhaul link when needed. The described power saving scheme may generalize across components of the monitoring system. Accordingly, access points, monitoring devices and peripheral sensors may put their communication interfaces (including backhaul link interfaces, IoT link interfaces, and/or local sensor data link interfaces) in a sleep mode when not needed.

Use Case II: Power Savings by a Subscriber, Using the IoT Communication Protocol Overlay

Turning to FIG. 11, a second power saving scheme implemented using the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, is shown. In the second power saving scheme, the amount of power consuming activity by a subscriber (e.g. a monitoring device) is regulated to reduce power consumption by the subscriber. As previously described, monitoring devices may be required to operate on battery for prolonged times up to multiple years. Accordingly, any power savings may be beneficial. One potentially power consuming service is the GPS location service. It may therefore be desirable to minimize the use of the GPS receivers of monitoring devices. The use of the built-in GPS receive may be controlled as follows. Using the IoT communication protocol overlay, a custom ratio of data payloads vs. data and GPS payloads may be adjusted, as illustrated in FIG. 11. The GPS receiver may be configured such that it is only activated when GPS data is required. Reducing the number of data frames that include GPS data therefore also reduces the activation of the GPS receiver, thereby significantly reducing power consumption. In FIG. 11, initially GPS data is included in every other data frame. However, a network management message then instructs the monitoring device to only provide GPS data with every third data frame thus reducing power consumption. Location data may, however, still be available with each data frame, e.g, if geolocation is performed using TDOA or RSSI methods.

Those skilled in the art will recognize that the second power saving scheme is not limited to the control of power consumption by GPS receivers. Instead, any power consuming components of monitoring devices may be controlled in a similar manner. Network management messages may thus be used to control various functions of monitoring devices by dynamically adjusting the ratio of data frame that include or exclude certain measurements.

Use Case III: Data Analytics Driven Network Management to Conserve Energy

As previously described, the transmit schedule for the subscribers can be managed, using the network management messages at the start of each frame. Data analytics on the network server side may thus be used to make data driven decisions regarding the activation of subscriber components. Transmit schedules may be updated, for example, for one or more of the following reasons:

-   -   Reducing subscriber power consumption during certain times of         the day (e.g. in a “night mode” in which GPS fixes may be less         frequent since the asset is not active during the night).         Periods of low activity, during which tracking frequency may be         reduced may further be learned from historically recorded data.         As an example, when tracking animals, activity analytics can         predict times of very low animal movement at night due to sleep         patterns and reduce sample rates over this time period.     -   Increasing the frequency of GPS fixes when an asset is near a         geo-fence (or triggering another alert condition).     -   Mapping of network dead spots, and using asset position history         to know that the asset is in the dead spot. Energy may thus be         conserved by significantly reducing the communication frequency         when the asset is believed to be in a dead spot, or approaching         a dead spot. A similar scheme may further be useful to reduce         false alarms (e.g., in case of an asset found to be off-site as         suggested by a single erroneous data point).     -   Mapping of GPS and/or TDOA dead spots. Other positioning methods         may be used in these known dead spots. This may conserve energy         and network processing resources, when the asset is determined         to be in a known TDOA and/or GPS dead spot.     -   Prolonging sensor lifetime when a low battery situation is         detected by lowering the sampling rate.     -   Adaptively adjusting subscriber transmission power based on         received beacon RSSI. Since the subscriber listens for the         beacon at the start of each frame, the subscriber can measure         the RSSI level of the downlink. The subscriber can then         calculate the required transmit power to meet the link budget on         uplink. This is helpful when the subscriber is close to the         access point and does not need high transmit power to meet the         link budget.     -   Using different beacons for different network functions, with         subscribers not being required to wake up for every beacon.         Accordingly, the frames in a superframe may be separated into         categories that each serve different functions. At the same         time, subscribers that are not a part of that function will stay         in low-power mode during that frame.

Use Case IV. Distribution of an Accurate Time Base to Enable TDOA Subscriber Localization

FIG. 12 shows a configuration of a monitoring system that enables TDOA methods to localize a monitoring device (1250) (or any other subscriber) by a group of at least three access points (1200) (for simplicity, only a single access point is shown), in accordance with one or more embodiments of the invention. Each access point includes a GPS interface (1214). In Step 1A, the GPS interface provides a precise location of the access point to the access point processing engine (1242). In Steps 1B and 1C, the GPS interface further provides an accurate time base to the IoT radio interface (1224) and to the time of arrival processing engine (1244), respectively. In Step 2, the IoT radio interface (1224) uses the provided time base to exactly time the transmission of radio signals to the subscribers, such as the monitoring device (1250). More specifically, the previously described beacon transmissions are timed, using the time base that was originally provided by the GPS interface. Because other access points rely on the same GPS-provided time base, all access points of an entire monitoring system may be synchronized. The transmission of the IoT radio interface, in addition to the time base, includes a network management message that specifies, using the previously described superframe framework, when precisely the monitoring device (1250) is supposed to respond to the access point(s). Accordingly, in Step 3, the monitoring device may, at the specified time, emit a transmission to the access point(s) (1200). In Step 4, the transmission is received by the radio interface (1224) of the access point (1200). Due to the transmission delay, as the message is traveling from the monitoring device (1250) to the access point (1200), the time when the transmission is received by the access point is not identical to the time when the transmission is sent by the monitoring device. In Step 5, through comparison of the time when the transmission is received to the time when the transmission was sent, corrected for known processing delays, the time of arrival processing engine may determine a time difference. This time difference may then be used to determine a distance between the monitoring device and the access point. The access point processing engine (1242) may perform a triangulation using the distances of the monitoring device from the access point and from at least two more access points that may have communicated their distances to the access point processing engine. Accordingly, it is the precise timing of communications, established using the IoT communication protocol overlay that enables TDOA positioning, even when the underlying protocol would not provide the required precise timing.

Use Case V: Data Analytics Driven Network Management to Increase Network Capacity and/or Reliability

-   -   Improving reliability and performance of data backhaul over a         Wi-Fi mesh by providing a known schedule, assisting in traffic         management. At each access point, sensor data is accumulated,         and the backhaul link between the high data rate backhaul         radio-sub system is active for bi-directional communications         starting at the furthest point in the mesh (the Nth Access         Point) down to the first (primary access point) in sequence         during each frame. Each access point, thus, only needs to         operate a small time fraction of each frame and an overall         processing delay of only one sub-frame is incurred. The data         rate of the back haul is one or more orders of magnitude         (factors of 10) higher than the entire IoT system bandwidth,         allowing these small time segments of activity relative to the         length of each frame.     -   Ability to increase network capacity by adding more frames to         the superframe. As the number of subscribers on a network         increases, more frames can be added to the superframe to support         the additional subscribers. In contrast, for a contention-based         network, the data throughput would drop once a certain number of         sensors has joined the network due to an increase in collisions.     -   Switching between subscriber modes. Different operating modes         may have been pre-loaded onto the subscriber device, or may have         been provided using an OTA firmware update. These modes may be         activated or deactivated by the network management messages.         Thus, subscribers can be switched into different modes and         operate on different beacons and/or frames.

FIG. 13 shows a computing system in accordance with one or more embodiments of the invention. Embodiments of the invention may be implemented on a computing system. Any combination of mobile, desktop, server, embedded, or other types of hardware may be used. For example, as shown in FIG. 13, the computing system (1300) may include one or more computer processor(s) (1302), associated memory (1304) (e.g., random access memory (RAM), cache memory, flash memory, etc.), one or more storage device(s) (1306) (e.g., a hard disk, an optical drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, a flash memory stick, etc.), and numerous other elements and functionalities. The computer processor(s) (1302) may be an integrated circuit for processing instructions. For example, the computer processor(s) may be one or more cores, or micro-cores of a processor. The computing system (1300) may also include one or more input device(s) (1310), such as a touchscreen, keyboard, mouse, microphone, touchpad, electronic pen, or any other type of input device. Further, the computing system (1300) may include one or more output device(s) (1308), such as a screen (e.g., a liquid crystal display (LCD), a plasma display, touchscreen, cathode ray tube (CRT) monitor, projector, or other display device), a printer, external storage, or any other output device. One or more of the output device(s) may be the same or different from the input device(s). The computing system (1300) may be connected to a network (1312) (e.g., a local area network (LAN), a wide area network (WAN) such as the Internet, mobile network, or any other type of network) via a network interface connection (not shown). The input and output device(s) may be locally or remotely (e.g., via the network (1312)) connected to the computer processor(s) (1302), memory (1304), and storage device(s) (1306). Many different types of computing systems exist, and the aforementioned input and output device(s) may take other forms.

Software instructions in the form of computer readable program code to perform embodiments of the invention may be stored, in whole or in part, temporarily or permanently, on a non-transitory computer readable medium such as a CD, DVD, storage device, a diskette, a tape, flash memory, physical memory, or any other computer readable storage medium. Specifically, the software instructions may correspond to computer readable program code that, when executed by a processor(s), is configured to perform embodiments of the invention.

Further, one or more elements of the aforementioned computing system (1300) may be located at a remote location and connected to the other elements over a network (1312). Further, embodiments of the invention may be implemented on a distributed system having a plurality of nodes, where each portion of the invention may be located on a different node within the distributed system. In one embodiment of the invention, the node corresponds to a distinct computing device. Alternatively, the node may correspond to a computer processor with associated physical memory. The node may alternatively correspond to a computer processor or micro-core of a computer processor with shared memory and/or resources.

FIG. 14 shows a flowchart describing methods for monitoring assets, in accordance with one or more embodiments of the invention. The method may be used, for example, to track the location of persons or equipment and/or physiological signals of tracked individuals. The method may be executed repeatedly over time, thus enabling a user to continuously monitor the assets and to detect changes, e.g., when the assets move, when their state changes or environmental conditions change, etc.

In Step 1400, monitoring data is collected from the assets that are equipped with monitoring devices. Data may be collected from the various sensors of a monitoring device, but also from peripheral sensors, if peripheral sensors are used. The collection may occur as scheduled, e.g., based on the time-base provided by the IoT communication protocol overlay or spontaneously, e.g., upon request or when a particular event is detected. The data collection by one monitoring device may be independent from the data collection by other monitoring devices. The collected data may be buffered by the monitoring device until it can be transmitted to an access point.

In Step 1402, the monitoring devices provide the collected data to one or more access points, using the IoT link. Each monitoring device uses a communication slot at a particular time and in a particular frequency band, as specified by the IoT communication protocol overlay, thus avoiding transmission interference by multiple monitoring devices using the same communication slot. The transmissions of the monitoring devices may be received by one or more access points within range.

In Step 1404, the received data may be processed by the access point(s) that received the data. The processing may include aggregating, filtering, fusing, compressing and/or encrypting the data. The processing may further include the exchange of data with other access points. For example, TDOA data may be exchanged between access points to determine a location of a tag sensor, relative to the access points.

In Step 1406, the processed data are provided to a hub, using the broadband link that interfaces the access point(s) and the hub. Step 806 is optional and is executed only if a hub exists in the used system configuration. If no hub exists, the processed data may alternatively be provided to the cloud. Regardless of whether the system is configured to use a hub, a cloud or both, the processed data is received by the hub/cloud platform which is executing on the hub, in the cloud, or on the hub and in the cloud.

In Step 1408, data analytics are performed by the hub/cloud platform executing on the hub. The data analytics may include modules that are generic to a variety of applications such as location tracking, and other modules that are specific to a particular application, such as equipment tracking in the oil & gas industry, monitoring physiological parameters of patients, etc. The data analytics may additionally or alternatively be performed in the cloud.

In Step 1410, the processed monitoring data is uploaded to the cloud. This step may be performed in systems that include a cloud environment and in systems that include a combination of the hub and the cloud. Accordingly, data obtained from the tag sensors may be equally accessible via the cloud and via the hub.

In Step 1412, a user is provided access to the processed monitoring data using the hub/cloud platform that is executing on the hub, in the cloud, or on the hub and in the cloud. The user may access the processed monitoring data using any type of computing device that is capable of interfacing with the hub/cloud platform. The user may obtain a visualization of the processed monitoring data, which may include text, graphics, charts, etc. The user may access a time history of the processed monitoring data and may further also access the unprocessed or partially processed data obtained from the tag sensors. Alerts may be provided to the user under certain configurable conditions. For example, an alert may be provided if a tracked equipment is leaving a particular area such as a parking lot, if unusual movement patterns (such as the lack of movement of an elderly patient, indicating a potential problem) are detected, or if physiological measurements are beyond a specified range.

FIG. 15 shows a flowchart describing a method for transmitting, by a monitoring device, a data value.

In Step 1500, a beacon is received by the monitoring device. The beacon may be similar to the beacon described with reference to FIGS. 7 and 8. The beacon may be received from one or more access points in the vicinity of the monitoring device

In Step 1502, a network management message is received by the monitoring device. The network management message may be included in the beacon, or it may be a separate transmission. The network management message, in accordance with an embodiment of the invention, specifies one or more data values to be gathered by one or more monitoring devices, and the communication slots to be used for the return of these data values. The communication slots may be specified using time values and frequency band values, as previously described with reference to FIG. 7.

In Step 1504, The monitoring device collects the data value(s), as instructed by the network management message. The data value may be collected by one or more sensing devices of the monitoring device, as previously described with reference to FIG. 4.

In Step 1506, a determination is made about whether the transmission time, specified in the management message has been reached. The method may proceed to Step 1508 if the transmission time has been reached. The transmission time may be, for example, a time offset measured from when the beacon was received.

In Step 1508, the data value(s) is transmitted to the access point, using the specified frequency band.

FIG. 16 shows a flowchart describing methods for receiving, by an access point, a data value. The flowchart of FIG. 16 may be complementary to the flowchart of FIG. 15.

In Step 1600, an access point obtains instructions, from a network management service. The instructions specify that a data value is to be collected by a sensing device of a monitoring device.

In Step 1602, the access point transmits a beacon.

In Step 1604, the access point transmits a network management message. The network management message may be included in the beacon, or it may be a separate transmission. The network management message, in accordance with an embodiment of the invention, specifies one or more data values to be gathered by one or more monitoring devices, and the communication slot(s) to be used for the return of this data value(s). The specification of the communication slot may include a time and a frequency band.

In Step 1606, the data value(s) is received.

In Step 1608, the data value(s) is forwarded, e.g., to another access point or directly to a hub, using a broadband uplink.

Various embodiments of the invention have one or more of the following advantages. Embodiments of the invention enable the upgrading of various underlying communication protocols to provide synchronous communication from subscribers to access points. The IoT communication protocol overlay, in accordance with one or more embodiments of the invention, establishes a precise timing that is sufficient to support even applications that require a highly accurate time base, such as TDOA positioning. The use of the IoT communication protocol overlay, in accordance with one or more embodiments of the invention, enables simultaneous operation of legacy devices that are not capable of using the IoT communication protocol overlay. In one or more embodiments of the invention, the IoT communication protocol overlay, through the precise, non-overlapping selection of uplink communication frequencies and timing, increases throughput, network capacity and robustness, while reducing interference with other networks. In one or more embodiments of the invention, the precise scheduling of transmissions enable precise control of communication transceiver components, thereby enabling increased power efficiency of access points and subscribers.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 

What is claimed is:
 1. A system comprising: a plurality of monitoring devices, wherein a first monitoring device among the plurality of monitoring devices comprises an Internet of Things (IoT) transceiver, a sensor, and a global positioning system (GPS) receiver; an access point configured to communicate with the plurality of monitoring devices, wherein the plurality of monitoring devices and the access point implement a communication protocol overlay, the communication protocol overlay comprising: a repeating pattern of superframes within an IoT protocol, each superframe comprising a plurality of frames, wherein the repeating pattern of superframes governs wireless data communication between the access point and the plurality of monitoring devices, wherein each frame of the plurality of frames comprises: a beacon emitted by an access point in a downlink communication to the plurality of monitoring devices at a beginning of the frame; a plurality of communication slots following the beacon and providing asynchronous communication with the access point, wherein each of the communication slots is uniquely assigned to a respective monitoring device of the plurality of monitoring devices, permitting the first monitoring device to perform an uplink communication to the access point, within the communication slot, wherein the beacon is precisely timed, wherein the plurality of communication slots comprise a first communication slot and a second communication slot that follow the beacon with a specified temporal offset, wherein the first communication slot and the second communication slot have a different frequency slot and a different time slot among the plurality of communication slots, wherein the first monitoring device is assigned the first communication slot in a first superframe among the repeating pattern of superframes, wherein the first monitoring device is reassigned to the second communication slot in a second superframe among the repeating pattern of superframes, wherein, a single superframe of the repeating pattern of superframes serves all monitoring devices of the plurality of monitoring devices by providing at least one communication slot to each of the plurality of monitoring devices, and wherein the first monitoring device transmits, during the first superframe, a first data payload comprising a first sensor data value and a GPS value, and wherein the first monitoring device transmits, during the second superframe, a second data payload comprising a second sensor data value and without any GPS data in the second data payload.
 2. The system of claim 1, wherein a subset of the plurality of communication slots is arranged sequentially in time.
 3. The system of claim 1, wherein a subset of the plurality of communication slots is arranged in parallel in time, using different communication frequencies.
 4. The system of claim 1, wherein the timing of the beacon is governed by a time base obtained by the global positioning system (GPS) receiver of the access point.
 5. The system of claim 1, wherein the communication protocol further governs wireless data communications between other access points and the plurality of monitoring devices.
 6. The system of claim 5, wherein the other access points emit the beacon in synchrony with the access point emitting the beacon.
 7. The system of claim 5, wherein an uplink communication by one of the plurality of monitoring devices, in the communication slot assigned to the monitoring device, is received by the access point and by the other access points.
 8. The system of claim 1, wherein the communication protocol overlay is placed on top of an underlying communication protocol.
 9. The system of claim 8, wherein the underlying communication protocol is a beacon-based communication protocol.
 10. The system of claim 8, wherein the underlying communication protocol operates at a plurality of communication frequencies, wherein only a subset of the plurality of communication frequencies is utilized by the communication protocol overlay, and wherein the communication frequencies of the plurality of communication frequencies that are not included in the subset are reserved for legacy devices not designed for the communication protocol overlay.
 11. The system of claim 1, wherein each frame further comprises a beacon guard time, following the plurality of communication slots, wherein the beacon guard time is reserved for special communications.
 12. The system of claim 11, wherein the special communications are one selected from a group consisting of a firmware over the air downlink and a high-priority communication.
 13. The system of claim 1, wherein the assignment of communication slots to the plurality of monitoring devices is periodically updated, thereby increasing noise immunity.
 14. The system of claim 1, wherein the frame is only partially occupied by the plurality of communication slots, and wherein during a frame portion that is not occupied by communication slots, the access point is switched into an energy-saving mode, during which the access point is not listening for uplink communications by the plurality of monitoring devices.
 15. The system of claim 1, further comprising a network management message provided by the access point to the plurality of monitoring devices in the downlink communication, wherein the network management message succeeds the beacon and precedes the plurality of communication slots.
 16. The system of claim 15, wherein the network management message includes instructions to selected monitoring devices of the plurality of monitoring devices to control operation of modules of the selected monitoring devices.
 17. The system of claim 15, wherein the network management message defines the assignment of the communication slots to the plurality of monitoring devices, within the frame.
 18. The system of claim 17, wherein a single communication slot in the frame is assigned to exactly one monitoring device.
 19. A method comprising: receiving a beacon by a monitoring device among a plurality of monitoring devices using a communication protocol overlay and from an access point that communicates with the plurality of monitoring devices, wherein the beacon establishes a time base in an asynchronous communication with the access point in the communication protocol overlay, wherein the communication protocol overlay is implemented by the plurality of monitoring devices and the access point and the communication protocol augments an Internet of Things (IoT) protocol, wherein the communication protocol overlay comprises a repeating pattern of superframes, each superframe comprising a plurality of frames and each frame of the plurality of frames comprises a plurality of communication slots comprising a first communication slot and a second communication slot that follow the beacon, wherein the first communication slot and the second communication slot have a different frequency slot and a different time slot among the plurality of communication slots, wherein the monitoring device is assigned the first communication slot in a first superframe among the repeating pattern of superframes, wherein the monitoring device is reassigned to the second communication slot in a second superframe among the repeating pattern of superframes, and wherein the monitoring device comprises an IoT transceiver, a sensing device, and GPS receiver; receiving, from the access point and using the communication protocol overlay, a network management message, wherein the network management message specifies time relative to the time base and frequency band for transmission of a data value by the monitoring device to the access point; collecting the data value by the sensing device of the monitoring device; making a determination, through the communication protocol overlay, that the time specified in the network management message is reached, and based on the determination: transmitting, using the communication protocol overlay, the data value using the frequency band specified in the network management message, and transmitting, by the monitoring device during the first superframe, a first data payload comprising a first sensor data value and a GPS value, and transmitting, by the monitoring device during the second superframe, a second data payload comprising a second sensor data value and without any GPS data in the second data payload.
 20. The system of claim 1, wherein the access point comprises a battery and a plurality of transceivers for a plurality of frequency channels, wherein the access point operates in a first predetermined power mode and a second predetermined power mode that uses less power than the first predetermined power mode, wherein, during the first predetermined power mode, the access point obtains sensor data values from the plurality of monitoring devices, wherein, during the second predetermined power mode, the access point obtains a second monitoring device as a new subscriber to the access point, and wherein only a subset of the plurality of frequency channels transmit and receive data during the second predetermined power mode. 